This invention relates to a fire retardant adhesive tissue and a method of manufacture, and more particularly to a fire retardant tissue paper which has been treated with a dispersion of fire retardant and adhesive to provide a tissue with the fire retardant solids disbursed within the tissue paper and adhesive dots on the surface.
Tissue paper is utilized in a wide variety of industrial applications. One such application is as a portion of a laminate utilized in automobiles for improving sound insulation. In addition to its sound insulation properties, it is highly desirable that the tissue paper be treated with a flame retardant so that the final product will be flame retardant and still have good acoustic properties when in composite form.
Tissue paper typically used in automotive applications is of a grade that has a weight of between about 17 to 21 g/m2 (0.5 to 0.6 oz/yd2). This is a difficult material to work with due to the extremely low tensile strength of the material. Since many flame retardant solids are provided in aqueous solutions, once the fragile tissue paper is wetted, it would tend to tear when being transported through the manufacturing process. Further, it is desirable not to have to apply the flame retardant and the adhesive in separate operations due to the fragile nature of the materials. Various processing options are available. This includes hot melt coating to apply the adhesive without causing the paper to become brittle or degrading the cellulose in the paper.
In view of the difficulty in handling a low tensile strength material such as tissue paper, it is highly desirable to provide a flame retardant adhesive tissue paper which can be manufactured without degrading the paper and which will overcome the processing difficulties in the prior art. Such a flame retardant adhesive tissue finds particular utility in automotive application where such papers are utilized in various vehicle interior laminates.
Generally speaking, in accordance with the invention, a flame retardant adhesive tissue paper for fabricating moldable structures and methods of fabrication of the tissue paper are provide. The flame retardant adhesive tissue paper is prepared by applying an aqueous paste dispersion including a flame retardant and thermoplastic adhesive dispersed therein to the surface of the paper using a printing screen. This coating adds 25 to 50% dry solids on the surface based on the weight of the paper. The amount of paste coating applied to the paper is controlled by the pumping speed of the dispersion to the screen-print head and the transport speed of the paper past the print head.
When an aqueous paste dispersion is screen printed onto the tissue paper and dried, the flame retardant solids in the paste dispersion wet out the paper leaving the adhesive dots on the surface of the paper. This causes the flame retardant solids to be soaked into the cellulosic material and impart flame retardant properties to the adhesive coated paper. After application of the dispersion, the paper goes through a forced air oven at controlled speed to dry off the water.
After drying, the flame retardant solids and polymer adhesives stay behind on the paper. After all the water is removed, oven temperature is increased to activate the polymer adhesive causing it to flow and adhere to the paper. As the coated paper leaves the oven, it is batched on rolls and ready for shipment.
Accordingly, it is an object of the invention to provide a tissue paper which has added flame retardant properties and thermoplastic adhesive dots on its surface.
Another object of the invention is to provide an improved flame retardant adhesive tissue paper including dots of thermoplastic adhesive on the surface and flame retardant solids dispersed in the cellulose material
A further object of the invention is to provide a process for preparing a flame retardant adhesive tissue paper having a weight about 15.5 to 22.0 g/m2 (0.45 to 0.65 oz/yd2).
Yet another object of the invention is to provide an improved flame retardant adhesive tissue paper wherein the flame retardant solids are dispersed within the cellulosic material of the tissue paper.
Yet a further object of the invention is to provide a flame retardant adhesive tissue wherein the flame retardant solids are dispersed within the tissue and the adhesive dots on the surface are of polyester.
Still a further object of the invention is to provide a method for preparing a flame retardant adhesive tissue without damaging tissue paper.
Still other objects and advantages of the invention will in part be obvious and will in part be apparent from the specification.
The invention, accordingly comprises an article possessing the characteristics, properties and relation of constituent, and the several steps of one of more of such steps with respect to each of the others, all as exemplified in the detailed disclosure hereinafter setforth, and the scope of the invention will be indicated in the claims.